Build a terraced end house with an additional unit (GÜ) on your own

How is that supposed to work? Are all the houses staggered? If not, it would look odd, wouldn’t it? The municipality really messed up on this one. Many have already said it, but such a type of construction belongs in the hands of a developer.

The middle house has to be built set back because it needs to have two parking spaces, and there is only room for those in front of the house. We, on the other hand, place our two parking spaces beside the house.

We don’t actually find it that bad – everyone can build individually here and doesn’t have to pay the high premiums charged by developers. It can be somewhat tedious at times – but because of the staggered construction, our terraced house stands “free” and therefore it feels a bit like a small single-family home.

That’s also why we have been planning since January, so we can start as soon as the development area opens. Since everyone builds their own terraced house here, it will get pretty tight later on with all the cranes needed. As it currently looks, we will be the first ones.

Today we unfortunately learned that our middle house neighbor will not be buying the plot after all

I have the feeling there has already been a change (?)

The municipality really made a mess of it for you. Many have already said so, but such a type of construction belongs in the hands of a developer.

We don’t actually find it that bad – everyone can build individually here and doesn’t have to pay the high markups from developers.

That’s exactly the problem: in informational events this attitude is repeatedly expressed by interested parties, and the municipalities then “learn” from this to make this very same mess again at the next opportunity. They don’t mean it badly, they just want to be re-elected ,-)

Since here everyone builds their own row house, it will later become quite cramped with all the many cranes needed.

It is precisely this crane logistics cacophony that causes a plot to remain undeveloped in the end.
Uncoordinated construction management was sometimes possible when 500 sqm and up were the standard plot size, but today this overwhelms even Pronto Salvatore and experienced stocking machine programmers.

As much as I usually hope to be wrong with my doomsaying, here there are reasons that unfortunately are increasingly obvious even to laypeople :-(

Now we wonder how it will go if the new middle house neighbor is only found after our construction has started? [...] Does anyone know for sure that in Baden-Württemberg one must always agree to underpinning?

I hope the legislator was less naïve here: just imagine if the deadline for the last entitled party to request underpinning had to expire before anyone in the construction area could start.

unimaginable if the deadline of the last party entitled to the underpinning request would first have to expire before anyone could start in the construction area.

I find the neighbor law clear – in NRW even somewhat more detailed with deadline specification. The builder informs the neighbor that he wants to erect a boundary wall and the neighbor has two months to consider whether to assert claims regarding the foundation execution.
If the transfer of possession has not taken place by the deadline and the seller has not asserted any claims, construction can be started at the builder’s discretion.
The underpinning request only comes into play when the building application has been submitted or the house already stands. In the first case, the builder could still kindly adjust the plan; once the slab has been poured, however, it’s too late.
Since the timing coordination of the various construction projects by individual builders usually does not succeed – as we also see here – I also consider it impossible that a first builder without a basement can prevent the second builder from having a basement. The second builder will always be able to rely on the neighbor law.

According to the building authority, we will be named the next candidate(s) very soon. Then we will see if the neighbor also wants a basement. However, since the other corner house is building a basement, he would be throwing money away twice if he didn’t build one. He would have to do a deep foundation himself there.

Assuming we can actually start in October, according to the general contractor, one could wait up to three weeks before the start of construction with the structural analysis and thus also with the decision on the deep foundation.

Therefore, we are optimistic that the issue will be resolved in about three months or that a buyer will be firmly decided by then.

He would then have to make a deep foundation himself there.

..., but the neighbor would have to pay for it if they have not yet submitted a building application.

..., which the neighbor would have to pay for, provided he has not yet submitted a building application.

The corner house will also be built with a basement very soon. Therefore, the middle house would then have to underpin our floor slab and the other corner house would have to have deeper foundations if the middle house does not want a basement.